Thanks!Insight map creator automatically creates the at5 files the Lowrance unit uses. There are a number of hoops you have to jump thru, but once you figure it out, it’s just time consuming, especially for the high zoom photos.
To get oriented, watch the YouTube video on making your own Lowrance HDS maps by Brian O’Dell. The one thing I think he missed is tagging the advanced raster option as shaded relief imagery and NOT satellite imagery.